This invention relates to a non-linear counting circuit.
More particularly, the invention is concerned with a circuit which receives on its input a plurality (P) of pulses and which issues on its output a number (N), e.g. in binary form, where N=f(p), f being a continuous non-linear function.
Such a circuit can have many applications. For example, it can be introduced in a calculating unit to generate non-linear functions of an input variable. It can also be used in electronic circuits associated with measuring sensors which issue information in the form of a frequency. This circuit is then used, for example, to linearise the issued information when the sensor does not issue on its output a frequency which is actually a linear function of the value of the magnitude being measured by the sensor. It can also be used in certain systems for temperature compensating the frequency of a time base consisting mainly of a quartz resonator, the temperature information used in such systems to achieve compensation being supplied in the form of a signal having a frequency which is roughly a linear function of temperature. As is known, the frequency issued by a quartz resonator is usually a substantially quadratic function of temperature. Frequency compensation therefore involves having to calculate the square of the frequency issued by the temperature sensor.
One possible way of solving this kind of problem would be to resort to a microprocessor programmed to perform the non-linear transformation. However, such a solution is too complex and thus too costly if the function to be generated is fairly simple and if it is always the same, or comes in a very limited number of forms.